Problems of neuroblastoma screening for 6 month olds and results of second screening for 18 month olds

Nationwide neuroblastoma mass screening for 6-month-old infants (first screening) was introduced in Japan in 1985. About 110 neuroblastoma cases are detected annually by the first screening and treated, with a survival rate of 97%. Sensitivity of the first screening (positive cases/positive cases+false negative cases) is about 75%, and the prognosis of false-negative cases is unfavorable. A second screening at 18 months of age was started to rescue false-negative cases in Miyagi Prefecture in May 1992. Of 62 neuroblastoma cases treated in our hospital since 1985, 40 cases had received the first screening. Twenty cases were positive at first screening, 18 cases were false negative, and 2 cases were false negative and picked up by the second screening. Age distribution of false-negative cases ranged from 12 to 83 months and included 12 cases younger than 36 months old. Only 5 of 18 false-negative cases are alive without the disease. From May 1992 to November 1993, 14,282 infants had received the second screening (compliance rate: about 75%), and 2 neuroblastoma cases were detected. The first case was stage III with paraortic lymph node metastases, Shimada UH, aneuploidy and negative N-myc amplification. The second case was stage II with Shimada FH, aneuploidy, and negative N-myc amplification. Both cases are alive now without the disease after undergoing radical operation and chemotherapy. The first screening is effective for early detection of neuroblastoma cases, but the sensitivity is insufficient; the authors recommend a second screening to rescue false-negative cases.

Factors governing re-infarction in patients with myocardial infarction in Japan

The subjects consisted of 2,733 patients with acute myocardial infarction (AMI) who were admitted to our 11 institutions between 1983 and 1988, examined by coronary arteriography, and discharged alive. The patients were followed for an average of 2.9 years after discharge. During the follow-up period, re-infarction occurred in 172 patients (6.3%). The factors associated with re-infarction were total cholesterol of more than 250 mg/dl, HDL-cholesterol of less than 35 mg/dl and diabetes mellitus. The rate of re-infarction was also high in patients who had had a previous infarction before admission, angina pectoris before or after the onset of AMI or multiple-vessel disease. In contrast, intracoronary thrombolysis reduced the rate of re-infarction.

Antinuclear antibodies in healthy aging people: a prospective study

In order to evaluate the expression of antinuclear antibodies (ANA) in normal elderly individuals over time and clinical significance, a cross-sectional ANA testing in healthy Japanese was performed, followed by annual evaluations of ANA positive aged (> or = 65 years) and a control group. ANA was more prevalent in the aged (11.4% vs. 3.8%) and most were persistent after 4 years. Anti-ssDNA and anti-histone antibodies were increased in aged ANA positive as compared to ANA negative controls. Except for a history of spontaneous abortion, there was no differences in clinical findings. HLA DRB1*0901 and the DQB1*0602 + 0302 + 0303 set of alleles were increased in ANA positive. Therefore, ANA in the aged were persistent, apparently directed toward chromatin elements, and shared MHC associations with autoimmune diseases. Longer follow-up may be necessary to improve the evaluation of clinical significance of ANA in the aged.

Sequence-dependent modulation of anticancer drug activities by 7-ethyl-10-hydroxycamptothecin in an HST-1 human squamous carcinoma cell line

BACKGROUND

We studied the modulatory effects of 7-ethyl-10-hydroxy-camptothecin (SN-38), an active metabolite of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin, on the antitumor activities of clinically important anticancer drugs including cisplatin (CDDP), 5-fluorouracil (5-FU), mitomycin C (MMC), etoposide (VP-16), and adriamycin (ADR).

MATERIALS AND METHODS

The HST-1 human carcinoma cells were treated with graded concentrations of these anticancer drugs either alone or in combination with IC50 concentration of SN-38, administered in several different treatment schedules, and antitumor activity was evaluated by the growth inhibition assay.

RESULTS

SN-38 potentiated the antitumor activity of CDDP in all schedules with a maximal effect observed with a simultaneous administration, while SN-38 enhanced the cytotoxicity of MMC, 5-FU, or VP-16 only in certain schedules. By contrast, SN-38 attenuated the anticancer effect of ADR in all schedules.

CONCLUSIONS

These results demonstrate that SN-38 may have the advantage of augmenting the anticancer activity in combination with CDDP, MMC, 5-FU, and VP-16, depending on the schedule of administration, and should thus be incorporated into the design of a clinical trial for obtaining maximal therapeutic synergy.

Clinicopathological study on pineocytoma

Six cases of pineocytoma, which had developed in the parenchyma of the adult pineal body, were examined immunohistochemically and under an electron microscope, after the malignancy of each case had been determined using our classification. One case was rated as grade 1 showing a lobular structure and resembling the normal pineal body. Two cases were rated as grade 2 without a lobular structure but with pineocytomatous rosettes (P-rosettes). Two cases were rated as grade 3 without P-rosettes but with few mitotic figures. One case was rated as grade 4 with marked cellular pleomorphism, numerous mitotic figures and necrotic foci. When examined immunohistochemically, neuron-specific enolase was positive but glial fibrillary acidic protein was negative in all cases. Under an electron microscope, all cases showed abortive synapses, and clear or dense core vesicles. These findings allow us to make two conclusions. First, pineocytoma is always a tumor of neuronal lineage, regardless of their grade of malignancy. Second, the grade 4 pineocytoma should be distinguished from the type of tumor classically called "pineoblastoma." That is, the former seems to be a biologically dedifferentiated tumor, while the latter seems to be biologically undifferentiated tumor.

Mechanisms of ergonovine-induced hyperconstriction of coronary artery after x-ray irradiation in pigs

Mechanisms of ergonovine-induced coronary hyperconstriction were examined in vivo and in vitro in miniature pigs. To provoke coronary hyperconstriction, the endothelium of a segment of a major branch of the left coronary artery was denuded in 19 Göttingen miniature pigs (4 to 6 months of age). In Group I (n = 12), the denuded site of the coronary artery was selectively irradiated with 15Gy of x-ray twice, 3 and 4 months after endothelial denudation. The remaining 7 pigs were not irradiated (Group II). The vasoconstrictive effect of intracoronary administration of ergonovine (1 to 1000 microgram) was examined angiographically 3 months (just before irradiation in group I) and 5 months after denudation in the two groups. After the angiographical study, the vessels were isolated and isometric tensions were measured in an organ chamber. In the in vivo studies, ergonovine-induced vasoconstriction at the denuded and x-ray irradiated site in Group I was significantly greater than that at the control site or that at the denuded site in Group II. Pretreatments with serotonin receptor blockers (ketanserin or methysergide) significantly attenuated ergonovine-induced hyperconstriction, while an alpha-adrenergic receptor blocker (prazosin) did not (% inhibition; ketanserin 74 +/- 9%, p < 0.01, methysergide 60 +/- 10%, p < 0.01, prazosin 9 +/- 5%, NS). In the in vitro studies, ergonovine produced significantly greater tension at the denuded and x-ray irradiated site (Group I) than at the control site or at the denuded site (Group II). Ergonovine-induced endothelium-dependent relaxation was impaired at the denuded site in both groups to a similar extent. These results suggest that ergonovine-induced hyperconstriction at the denuded and x-ray irradiated coronary artery resulted mainly from the hyperreactivity of medial smooth muscle mediated by serotonin receptors.

The prevalence of obsessive-compulsive disorder in Japan: a study of students using the Maudsley Obsessional-Compulsive Inventory and DSM-III-R

The prevalence of obsessive-compulsive disorder (OCD) was measured in 424 Japanese students using a Japanese version of the Maudsley Obsession-Compulsive Inventory (MOCI-J). Six students (1.7%) of 350 interviewed students were diagnosed as OCD according to DSM-III-R. When the cut-off point of the MOCI-J was 12, the sensitivity was 100% and the specificity was 96%. Our results suggest that individuals with OCD are not rare among the young Japanese population and that the MOCI-J is a useful tool for screening OCD.

Optimal pH for preserving the activity of Mycobacterium leprae during incubation of cells in a cell-free liquid medium

The effect of the pH of a cell-free liquid medium on the activity of Mycobacterium leprae during incubation of the cells was investigated. As a parameter for evaluating the activity, the amount of adenosine triphosphate (ATP) extracted from the incubated cells collected by centrifugation was measured. The results demonstrate that the activity of M. leprae cells was maintained at a significant level for approximately 4 weeks at 30 degrees C in 0.05 M phosphate buffer containing 10% fetal calf serum at pH 7.0 compared to cells at other pHs tested, but activity was not preserved in phosphate buffer at pH 7.0 without serum and incubated at 37 degrees C. The maintenance of the activity under these conditions was prolonged somewhat by the addition of glycerin (2%) to the medium, and was definitely inhibited by rifampin but not by either penicillin or isoniazid. From the results reported here, it could be postulated that the optimal pH of cell-free media for the study of cultivation of M. leprae is 7.0.

The effects of non-interval PUVA therapy on the plaque stage of mycosis fungoides

The effectiveness of non-interval topical PUVA treatment was studied in four patients with mycosis fungoides at the plaque stage. Five regions of each patient were exposed to UVA immediately, 30 minutes, 60 minutes, 90 minutes, and 120 minutes, after topical application of 8-methoxypsoralen, respectively. The effects of these treatments were evaluated by clinical appearance and histological findings after the 20th treatment. All five regions were more improved clinically and histologically than the control region, which was not given PUVA therapy. There were no clear differences clinically among these five regions. Biopsy specimens from each region revealed the disappearance of epidermotropism and a marked decrease in atypical mononuclear cell infiltrations in the dermis. From these data, we concluded that there were no clear differences between these five treatments clinically or histologically and that non-interval PUVA therapy is useful for the early stages of mycosis fungoides. To our knowledge, this is the first report of non-interval PUVA therapy for mycosis fungoides.

Synthesis and evaluation of novel nonpeptide angiotensin II receptor antagonists: imidazo[4,5-c]pyridine derivatives with an aromatic substituent

Starting from recently reported nonpeptidic angiotensin II (AII) receptor antagonists, we have designed and prepared a new series of 6-arylimidazo[4,5-c]pyridine derivatives. Variation of phenyl groups at the 4-, 6- or 7-position of imidazo[4,5-c]pyridine showed that substitution at the 6-position resulted in receptor-binding activity almost as potent as that of DuP 753. This led to synthesis and evaluation of an extensive series of 6-aryl-imidazo[4,5-c]pyridine derivatives. Some of them were 4-fold more potent in vitro than DuP 753, but only showed weak antihypertensive activity in vivo when given orally to rats.

Immunocytochemical localization of platelet-type arachidonate 12-lipoxygenase in mouse blood cells

Arachidonate 12-lipoxygenase is an enzyme that oxygenates the 12 position of arachidonic acid to produce its 12-hydroperoxy derivative. We were interested in the tissue distribution and subcellular localization of the platelet-type 12-lipoxygenase, which is distinguished from the leukocyte type by several criteria. Antiserum was raised in rabbits against purified recombinant arachidonate 12-lipoxygenase of human platelets. When mouse bone marrow cells and lung were immunostained and observed by light and electron microscopy, the positively stained cells were platelets, megakaryocytes, and eosinophils. 12-Lipoxygenase was localized in the cytoplasm of platelets but was hardly detectable in the plasma membrane and intracellular organelles. The enzyme was found in the cytoplasm of immature megakaryocytes with kidney-shaped nuclei and a few profiles of demarcation membranes, as well as in the mature form with well-developed demarcation membranes. These results indicated the expression of 12-lipoxygenase at an early stage in the course of megakaryocytopoiesis.

Sudden sound-induced death in magnesium-deficient rats after repetitive episodes of seizures result from brain dysfunction

To clarify the changes occurring in EEG and ECG from seizure induction to sudden death, 25 weanling male Sprague-Dawley rats were fed a severely Mg-deficient diet for 18 days. In nine of 25 Mg-deficient rats, both EEG and ECG were recorded from the beginning of seizures induction until sudden death. When flattening of EEG became after seizure occurrence, all nine Mg-deficient rats did not recover and death occurred within a few minutes. These results may support the idea that sudden death in Mg-deficient rats resulted from brain dysfunction after repetitive episodes of noise-induced seizures and not from simple apnoea due to tonic contraction of respiratory muscle.

Plasminogen activators in tissue extract of aural cholesteatoma

Using a biochemical technique, the authors characterized and identified the plasminogen activator (PA) derived from tissue extracts of six aural cholesteatomas. The results of fibrin zymography indicated that the tissue extracts of two cholesteatomas demonstrated two lytic zones on fibrin-agarose plates. One of the lytic zones was at about 72 kd, while the other zone was at about 64 kd. Using various goat immunoglobulin G (IgG)-containing antibodies (anti-human uterine tissue type PA (t-PA), anti-human low-molecular-weight (LMW) urokinase, and nonspecific goat IgG) and plasminogen-free fibrin-agarose plates, we confirmed that the cholesteatoma tissue extracts contained 72 kd t-PA and 64 kd urokinase type PA (u-PA). Furthermore, we measured the t-PA and u-PA activities in the tissue extracts selectively by parabolic rate assay. In order to estimate the PA activity, we developed optimal conditions for this assay. The specific t-PA activity ranged from 0.03 to 0.43 mIU/micrograms-protein and the specific u-PA activity ranged from 0 to 0.35 mIU/microgram-protein. The highest percentage of u-PA with respect to the total PA activity was 44.9%. However, in four of the six cases, we failed to detect u-PA activity. In the present study, we thus clarified the presence of PAs in tissue extracts of aural cholesteatomas. Furthermore, we confirmed that measureable u-PA occurred in some tissue extracts. We anticipate that the u-PA in inflammatory tissues plays an important role in the degradation of the extracellular matrix via the formation of plasmin and collagenases.

[Cerebral blood flow and metabolism in Lafora disease]

An 18-year-old male manifesting intellectual deterioration and negative myoclonus was diagnosed as Lafora disease by the demonstration of Lafora bodies in the skin and muscle biopsy. The cortical evoked potential to electric stimulation of the median nerve at wrist showed the giant SEP, suggesting hyperexcitability of the sensory motor cortex. Cerebral blood flow, and cerebral glucose and oxygen metabolism were investigated by positron emission tomography (PET) in order to clarify the pathophysiological process in Lafora disease. The result showed diffusely decreased cortical glucose metabolic rate and cerebral blood flow, and moderately lowered oxygen metabolic rate. There was no increase in blood flow or glucose and oxygen metabolism in the sensorimotor cortex in spite of the presence of giant SEP. The ratio of the glucose to oxygen metabolism was not different from the mean value obtained from nine normal subjects. Based on these findings and review of the literature, it is unlikely that there is a significant deficit in cortical energy metabolism in patients with Lafora disease and it would be less plausible to have some enzymatic deficits in glucose metabolic process.

Impaired cholinergic peripheral vasodilation and its relationship to hyperemic calf blood flow response and exercise intolerance in patients with chronic heart failure

This study examined the peripheral endothelium-dependent vasodilatory response to acetylcholine and the endothelium-independent vasodilatory response to nitroprusside in 19 patients with chronic heart failure and eight controls. These peripheral blood flow responses were compared with hyperemic calf blood flow changes after maximum leg exercise and 5-min femoral occlusion. The peripheral blood flow response to forearm intra-arterial infusion of acetylcholine and sodium nitroprusside, and reactive hyperemic calf blood flow changes were measured by plethysmography. All peripheral blood flow responses were significantly reduced in patients with chronic heart failure (P < 0.05). Reduction of acetylcholine-mediated changes in peripheral blood flow was correlated with exercise-induced calf blood flow response (r = 0.51, P < 0.05), but not with occlusion-induced calf blood flow response (r = 0.02, NS). Sodium nitroprusside-mediated changes were not correlated with any reactive hyperemic blood flow responses (exercise: r = 0.27, NS; occlusion: r = 0.11, NS). When the patients were divided into two subgroups based on the median exercise-induced calf blood flow change, the subgroup with the lower calf blood flow response showed a reduction in exercise capacity (anaerobic threshold: 11.8 +/- 0.6 vs. 14.6 +/- 1.0 ml/kg/min; P < 0.05). These findings suggest that endothelial dysfunction is related to a decrease in exercise-induced skeletal muscle blood flow and exercise capacity in patients with chronic heart failure.

Effect of lipopolysaccharide on thymidine salvage as related to macrophage activation

Lipopolysaccharide (LPS), known as one of the potent activators of macrophages, has inhibitory effects on the proliferation of normal macrophages and macrophage-like cell lines. We report here that LPS dose- and time-dependently suppressed the tritiated thymidine ([3H]TdR) incorporation into the acid-insoluble fraction with a significant inverse correlation to the tumour necrosis factor-alpha (TNF) production in the J774.1 macrophage cell line. Among the three tested enzymes involved in DNA synthesis, only thymidine kinase (TK) activity decreased progressively in parallel with the decline in [3H]TdR incorporation, reaching 97% inhibition within 12 hr of LPS treatment, while changes in the activities of other two enzymes, DNA polymerase alpha and thymidylate synthase (TS), were less significant. On the other hand, LPS inhibited the cell proliferation only incompletely, as judged by 62% inhibition of cell growth at 36 hr. Even in the experiments done in a TdR-free medium, cell growth was inhibited by LPS to the same extent, suggesting that TK was not directly involved in the proliferation of J774 cells. LPS also inhibited the conversion of TdR to thymidine monophosphate (TMP) in murine peritoneal exudate macrophages (PEM). Thus LPS-induced suppression of TdR salvage related to TNF production is common in both normal and neoplastic macrophages, and therefore may be of potential importance in the process of macrophage activation.

Uptake site of lansoprazole, a proton pump inhibitor, in human fundic mucosa: possible relevance with fibroblast and Helicobacter pylori

To clarify the mechanism of the effect of lansoprazole in the healing of human gastric ulcer, the uptake sites of lansoprazole were studied using endoscopically biopsied specimens from the margin of the gastric ulcer. The specimens were incubated in a medium containing 3H-lansoprazole for 5 or 15 min., postfixed with 1% osmic acid and embedded in Epon. The semithin or ultrathin sections were made and radioautographic emulsion films were applied by the wire-loop method. 30 days after the incubation, the sections were developed, fixed and observed by light and electron microscopy. As a result, the uptake sites of lansoprazole were accumulated on the fibroblasts located near the tip portion of the gastric mucosa and on the unmyelinated nerve fibers as well as on the parietal cells. Some of the uptake sites were also observed near the plasma membrane of the bacteria in the gastric lumen. From these observations, lansoprazole uptake sites were not only on the parietal cells but on the fibroblasts and the bacteria, suggesting that the effect of lansoprazole was exerted partly through the influence on the mesenchymal cells and Helicobacter pylori-related organisms.

Expression of human platelet-activating factor receptor gene in EoL-1 cells following butyrate-induced differentiation

Platelet-activating factor (PAF) is a potent lipid mediator of allergic inflammation through its interaction with eosinophils. Expression of the PAF receptor is modulated by many agents, including those responsible for cell differentiation. We report here that differentiation of a human eosinophilic leukaemia cell line, EoL-1, by sodium n-butyrate is associated with induction of PAF receptor gene expression, as indicated by: PAF receptor mRNA accumulation; increases in the binding of [3H]WEB 2086, a PAF antagonist; analysis of cell-surface expression of PAF receptor protein using a monoclonal anti-(PAF receptor) antibody; and augmentation of PAF-induced increase in the intracellular concentration of calcium. Using cDNA cloning, the receptor expressed in EoL-1 cells was identified as 'Transcript 1', one of two transcripts which was previously reported from human genomic analysis (Mutoh, Bito, Minami, Nakamura, Honda, Izumi, Nakata, Kurachi, Terano and Shimizu (1993) FEBS Lett. 322, 129-134). The PAF-induced calcium response and phosphoinositide turnover were decreased by pertussis toxin (PTX) treatment, suggesting that these signals are coupled largely with PTX-sensitive G-protein(s) in EoL-1 cells. These systems may provide a useful experimental model with which to investigate the relationship between eosinophilic differentiation and PAF receptor induction, and the role of eosinophils in allergic responses.

[A young woman with rheumatoid arthritis who rapidly developed secondary amyloidosis]

A 22-year-old woman, who had been diagnosed as having rheumatoid arthritis (RA) 2 years before, was admitted to our hospital complaining of watery diarrhea (several times/day). She had been treated with low dose prednisolone (PSL) and auranofin in out-patient clinic. On admission, laboratory data showed moderate proteinuria (0.3 g/day) and positive CRP (2.7 mg/dl). Although the activity of RA was controlled by the administration of low dose methotrexate (7.5 mg/week) in addition to PSL, watery diarrhea and proteinuria did not improve. The biopsy of the stomach, rectum and kidney revealed the deposition of AA type amyloid protein, resulting in the diagnosis of secondary amyloidosis. Secondary amyloidosis has been reported as one of the common complications in RA patients, especially in old patients with a long history of RA. To our knowledge, however, there have been few reported cases who developed secondary amyloidosis so early during the course of RA as our case. We should be careful for the development of secondary amyloidosis even in young RA patients with short history of RA, when the disease is active.

Systematic approach to a dosage regimen for phenytoin based on one-point, steady-state plasma concentration

A systematic approach to individualizing the phenytoin (PHT) dose from a previous dose (D) and steady-state concentration (Css) pair was established by the combined use of two methods based on recently reported population pharmacokinetic parameters. This system applies the Michaelis-Menten equation to the initial data pair (D1-Css1) and solves for (a) maximum metabolic rate constant (Vmax) assuming the population mean for the Michaelis constant (Km) (method 1), and (b) Km assuming the population mean for Vmax (method 2). The derived estimates of Vmax and Km are then put through a series of filters, which results in the selection of method 1 and/or method 2 or allocation of a third category that needs further evaluation. A simulation study was performed to find a series of filters. The presented approach was applied retrospectively to the patients' data of 35 sets. Accurate predictions of the Css error within 5 micrograms/ml were obtained in 84% of the 25 cases, and in 30% of the 10 cases excluded. This systematic approach gives better prediction performance in mean error, mean absolute error, and root mean square error than a Bayesian feedback method.

[A case of rigid spine syndrome with congenital cardiac abnormality of sinus venosus defect]

A 28-year-old male with a rigid spine syndrome who had congenital cardiac abnormality of sinus venosus defect was described. The patient was admitted to our hospital because of easy fatigability and palpitation. At the age of 4 years, he had an operation for his congenital cardiac abnormality and developed persistent atrial fibrillation thereafter. On neurological examination, he had average mentality, rigid spine with joint contractures, especially in the left elbow joint, and winged scapulae. He had marked muscle weakness and atrophy, predominantly in the left half of the extremities and trunk. Electromyographic studies demonstrated myopathic with partial neurogenic changes. Motor and sensory nerve conduction velocity was normal. A muscle biopsy specimen obtained from the right rectus femoris showed some marked hypertrophic and atrophic muscle fibers, with prominent internal nuclei, fiber splitting and pyknotic nuclear clump. ATP-ase stain showed type 2B fiber deficiency, increased number of type 2C fibers and fiber type grouping.

Human nonspecific suppressor factor (hNSF): cell source and effects on T and B lymphocytes

The human nonspecific suppressor factor (hNSF), the probable counterpart of the murine monoclonal nonspecific suppressor factor (MNSF), has been isolated from the ascitic fluid of a patient with systemic lupus erythematosus and characterized. hNSF presents an inhibitory activity on the proliferation and IgG production of mitogen stimulated human PBMC. In the present study, we demonstrate that hNSF can be isolated from the supernatants of ConA-activated T cells, but not from CD8-depleted T cells, indicating the CD8+ T cells are the major source of the factor. We also studied the effects of hNSF on purified human B and T cells; hNSF strongly inhibited the proliferation and Ig secretion by highly purified B cells induced by SAC plus IL-2, as well as the proliferation of T cells activated by Con A plus IL-2. These results indicate that hNSF is a CD8+ T cell product with strong antigen-nonspecific immunoregulatory action on both lymphocyte populations.

Expression of c-kit receptor (CD117) and CD34 in leukemic cells

The expression of c-kit receptor (c-kit R; CD117) and CD34 was examined in acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), chronic myeloid leukemia (CML) in blastic transformation (BT), and myelofibrosis (MF) in myeloid BT. In myeloid leukemia including AML, CML-myeloid BT and MF-myeloid BT, both c-kit R and CD34 were expressed synchronously, while in lymphoid leukemia including ALL and CML-lymphoid BT, only CD34 was highly expressed. A close correlation between c-kit R and CD33 expression and an inverse correlation between c-kit R and CD19 expression were observed when all of the myeloid plus lymphoid leukemia cells were analysed. There was a close correlation between c-kit R and CD34 expression in the myeloid leukemia cells. c-kit R expression may be associated with myeloid phenotypes of leukemic cells and may be useful for the diagnosis of myeloid leukemia. The literature of c-kit R expression in leukemic cells is reviewed here and the comparison of c-kit R and CD34 expression in normal hematopoietic progenitor cells with those on the leukemic counterparts was discussed.